| With the rapid development of China's economy,the demand for energy in a various of industries is increasing.With the raise of china's environmental protection laws and the implement of energy saving and emission reduction policy as well as the adjustment of national energy structure,developmen and utilization of new energy represented by wind power become the new direction of energy structure adjustment of our country since the 20th century.With the development of large-scale wind power plants,clean energy has gradually become a new force to promote the healthy development of China's economy.In practical engineering,the wind generator foundation is an important structure to carry the upper power generation system.To ensure its safe production,it is necessary to guarantee the structural safety of the wind generator foundation.The wind turbine is a typical high-rise structure,whose structure is subjected to the complicated external loads and the vibration of the upper tower and fan impeller,which affect the stability of the lower foundation.The vibration of the fan base will experience more than ten million times in the life of the period for 20 years,so the force analysis of cyclic loading on the fan base is needed to evaluate the fatigue damage of the key nodes in view of the existing project example as the background.To solve this problem,the following work is carried out:1.The theoretical basis and analysis method of dynamic response analysis,concrete fatigue damage and steel material fatigue damage are summarized.This paper mainly introduces the theory of fatigue damage,including s-n curve and Miner linear cumulative damage.At the same time,several theoretical analysis processes such as rain flow counting and modal analysis are introduced to provide theoretical support and calculation method for the subsequent structural dynamic analysis and base on the calculation of fatigue damage.2.Wind simulation method of the analysis object is provided and compared by summarizing the relevant theories of wind simulation.This paper mainly studies the structural dynamic response analysis and structural fatigue damage analysis.Therefore,wind simulation method is chosen based on time domain analysis.MATLABA simulation program is utilized to pulsate wind speed time history data verified by the standard wind element spectrum Davenport spectrum through the theory of the mathematical model and relevant calculation method,it is found that the data of wind speed is consistent with Davenport spectrum,and the simulation results are agree well with the theoretical results.3.The calculation method of wind load for different components of wind turbine is found by summarizing the relationship between wind speed and wind load.Calculation of wind turbines by axial wind load and calculation of the limit of wind load under wind load in normal working condition have different empirical formula and evvh theory calculations,which is based on "load code for the design of building structures" to calculate tower drum wind load of the fan.The dynamic load of different components can be obtained by taking the wind speed data in the wind simulation.4.The finite element software ABAQUS was used for building the model,and the wind load time data loading model was calculated.By analyzing the fatigue damage of the basic concrete,it can be shown that the most vulnerable part of the fan foundation is the concrete in the direction of the fan blade.Moreover,the concrete fatigue damage caused by the normal working conditions of 12m/s is the largest.5.According to the structural dynamic analysis and the fatigue hot spot stress time history of relevant point data,s-n curve and fatigue calculation methods of Miner linear cumulative damage theory are used to calculate the vulnerable point in the life cycle fatigue damage.The results show that the most disadvantage of the basic fatigue life is the mutation or inhomogeneity of the material in the windward and leeward side.Fatigue evaluation is performed on the stress of target point. |
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